Wireless Mobile networks, such as UMTS, CDMA, LTE, and WIMAX, use layered network architectures that are broadly partitioned as an Access Network (AN) that deals with authorizing a user's access to a specific wireless network, his service plans, and his level of authorization (for example Adult vs. Child); and a Core Network (CN) that connects user plane sessions to the internet and other networks while enforcing the operator policies determined during the session establishment through the access network. After a session, such as a PDP Context or EPC Session, is established, the network devices in the access network, such as the NodeB, eNodeB, BTS, BSC, and RNC, are unaware of the type of application being used or the content type. These devices are also unaware of the corresponding network bandwidth/delay/jitter requirements of applications that are transported over the established user-plane tunnels. Similarly, network devices in the core network, the internet and content servers are unaware of the transit network conditions. These transit network conditions may include congestion in a specific sector, or a specific device, such as NodeB, or RNC. Other conditions include that the user may have moved to a location where the wireless coverage is poor, or the voice call volume in the specific sector/location has increased, thus reducing the available capacity in certain location. Network protocols, such as TCP, attempt to adjust to the maximum available capacity that the underlying transport could support by using end-to-end acknowledgements. However, each of these TCP sessions is unaware of other sessions in that sector or congestion point. Moreover, all of the TCP sessions associated with a specific UE, or with multiple UEs in the same sector, NodeB, or RNC may not be traversing the same Core Network devices, such as SGSN, or GGSN. Attempts by each TCP session to maximize network usage may not be suitable for certain applications and other TCP connections through the same congestion point.
As stated above, the congestion of the radio access network (RAN) is a major concern for operators of high-speed 3G networks. The problem is further exacerbated by the proliferation of smart phones and USB dongles to laptops that drive increasingly large amounts of data through the network compared to the older handsets. Such congestion could be due to small number of users running high bandwidth applications or due to the increased number of circuit switched (CS) users in a sector, the increased number of packet switched (PS) sessions, increased signaling rates in control plane (CS or PS), increased SMS or MMS usage during events or frequent RAB establishment and releases by certain devices or applications. In addition to congestion, wireless channel quality for a subscriber, which changes rapidly with mobility or due to contention with other users in the same sector/site, also makes it difficult for applications to deliver traffic consistently through the Radio Access Network (RAN). Devices in the RAN, such as NodeB, eNodeB, and RNC, are responsible for establishing user plane sessions (circuit switched or packet switched) and delivering packets to the established session by managing RAN/RF resources. These devices are unaware of the user application protocols, the network domains that the users access and the service requirements while accessing these domains. While 3GPP defines four broad categories of service classes (conversational, streaming, interactive, and background), the majority of user access patterns show conversational class for voice service, and interactive class while accessing internet. The rapid growth of mobile applications and the access density of the diverse applications in certain locations and during busy hours make the limited service classes inadequate for mobile operators to control and optimize RAN so that a user's quality of experience (QOE) is not severely degraded. Additionally, TCP/IP and the majority of applications that use TCP/IP are reservation-less protocols that use the network bandwidth to the extent that the underlying transport can support. The devices in the operator public land mobile network (PLMN) that process user application layer packets, such as TCP/IP/HTTP, and UDP, do not have the visibility of aggregation and congestion points in the operator wireless RAN. U.S. Pat. Nos. 8,111,630 and 8,208,430, which are incorporated by reference in their entireties, identify methods of placing a transparent proxy in RAN that intercepts Control Plane (CP) and User Plane (UP) in a plurality of domains (circuit switched and packet switched domains) and delivers cached content and performs other service delivery optimizations. The proxy identified in these patents proposes inline caching of accessed data and other application-specific optimizations that reduce the burden on the operator's core network, while improving the QoE of the end user.
FIG. 1 shows a sample inline network device deployed between the RNC and the SGSN. These inline network devices are usually transparent, and, when deployed outside of a base station or a radio network controller, do not have access to the congestion level within a network element or the user channel quality or the radio utilization. It is also not easy to estimate the RAN congestion level just by measuring the traffic flow to the RAN through the proxy device, because RAN capacity and user channel capacity are highly variable entities that depend on the distribution of users in the sector and the radio power allocation with voice and data among other things. However, proxies can benefit immensely from knowing the current RAN state, because they can tailor their services to the requirements of the RAN. For example, assume that a RAN cache proxy has two versions of a cached video, one in a higher resolution than the other. If the proxy could know that the user requesting the video is in a congested sector or has a bad radio channel, it can avoid overloading the RAN by serving the user with a lower resolution video. Many such optimizations are possible with an awareness of the RAN state.
Devices within the RAN, such as the RNC, NodeB, and eNodeB, deal with packet delivery over established user plane tunnels, and are unaware of the application/content types, and application needs. As described above, 3GPP standard define four service classes, (1) Conversational, (2) Streaming, (3) Interactive, (4) Background. Most application start by using the interactive service class using HTTP transport, and migrate to other application types based on user selection of a link on a web object. Additionally, the growth of mobile applications/widgets and their network usage pattern makes the above 3GPP defined services classes inadequate. More dynamic methods of identifying per flow short term network usage, longer term usage by the subscriber, subscriber-device, domain (web-site) and exporting in a consolidated way to RAN and core devices in the operator's mobile network facilitates network tuning and policy control of the network are required. This also facilitates better content adaptation for optimal QOE by the applications.
U.S. Pat. No. 8,111,630 defines methods and procedures for optimized content delivery by caching, split-TCP, transit buffering etc., in a transit network device placed in RAN that intercepts User Plane and Control plane protocols.
It would be beneficial if the transit network congestion information were propagated in a timely fashion to the core network devices that perform Policy Control Enforcement function (PCEF) or to a load balancer or to application/content delivery optimization devices. In this way, these devices could perform admittance control or video transcoding/transrating etc. functions better. Similarly, if the type of user application and its bandwidth expectations are known to devices in the RAN that are allocating Radio Resources, these devices could prioritize channel allocation based on content knowledge. Thus, it would be beneficial if there were methods that summarize the learned and estimated information from Control Plane and User Plane flows in the RAN, associate that information with sectors that they correspond to and export the consolidated information to other devices in RAN, CN, client device and Internet.